Microbiology

BoFU-80: Ultrasound assisted MALDI-TOF identification of Rhizopus oryzae

Rhizopus oryzae is commonly exist in soil, air, and other substances. It is an important mold in food fermentation because it can cause food decay. Its colony is loose or dense, which initially white and then turns gray brown to black brown. False roots are well-developed, with finger or root like branching, and are typical filamentous fungi that are difficult to break through. The protein was extracted by using standard formic acid extraction method that recommended by Bruker and identified with MALDI-TOF, but no obvious marker peak was found and could not be detected. After using a reagent kit for cell wall breaking and extraction, three characteristic peaks were identified, but there was a lot of noise, and the mass ratio (m/z) of the peak was less than 200.

The BoFU-80 uses a high-frequency focused ultrasound system to concentrate the acoustic energy into the sample to be processed, which can improve the protein extraction rate of the strain effectively and enhance the detection rate of the MALDI-TOF system. Using focused ultrasound and reagent kit to extract protein for MALDI-TOF detection, six marker peaks were obtained, with a peak to mass ratio (m/z) greater than 400 and a score of 9.169 indicating high confidence.